What I really needed to round off the experience was a good old railway pie with a dollop of tomato sauce on top.

That's because this first leg of my journey around New Zealand by rail - from Auckland to Ohakune - was as much a trip down memory lane as it was a great travel opportunity.

Partly that was thanks to the man sitting in the next seat, Richard Croker, newly retired after 52 years building railways, for whom every bridge and siding prompted stories of the great days of rail.

But also it was, for me, a reminder of journeys of yesteryear on the old Limited Express from Auckland to Wellington.

And the memories that came to mind were not of the fabulous scenery whizzing by outside the panoramic windows of the Overlander train, because the Limited ran through the night. Rather, they were of long, sleepless hours, ferociously uncomfortable seats and midnight stops at Taihape or Taumarunui for thick china cups of stewed tea poured from giant teapots, with the milk already added, sweet rock cakes, whose texture reflected the name, and hot savoury pies with tomato sauce.

The chunky cups have long gone. In fact, Richard recalled that they now sell for $40-$50. Amazing.

And that reminded him of how some of the old-time stewards used to collect the cups and saucers on a trolley pushed down the aisle "and then tip them out the door to save having to wash up".

As a result, there are places along the line where you can still find great piles of NZ Railways china.

"When we were working on the electrification of the main trunk back in the 80s," Richard recalled, "around Frankton we dug up lots of cups and saucers."

These days passengers don't even get off in Taumarunui - though Taihape is now back on the list of on-demand stopping places - because the Overlander has a buffet car, drinks come in plastic containers with nice pictures of TranzScenic trains printed on them, and far from getting stewed tea with the milk already added, I was able to choose a nice cup of weak Earl Grey with no milk.

The rock cakes have gone too. For morning tea, a couple of hours after we had pulled out of Britomart Station, I had a tasty Anzac biscuit.

But they do still have railway pies. The menu for the buffet cars has all sorts of newfangled stuff like tortilla wraps, chicken and almond sandwiches and butter bean salads. And, yes, The Great Railway Pie, filled with classic mince and baked fresh each day by Eve's Pantry. Yum.

I read the menu as we were pulling out of Britomart, admiring the spectacular harbour views where the line runs along the Auckland seafront, but it was only 8.40am - the train was supposed to depart even earlier at 7.30am but there had been problems with a generator - and still a bit early for a pie.

So I postponed thoughts of a purchase and chatted to Richard about the irony of the fact that from 1885 the Auckland station was at Britomart, but was moved to Parnell in 1929 to make way for a majestic new Chief Post Office, which has now 80 years later been transformed back into a station. Plus ca change, plus c'est la meme chose, as the old railway workers would have said.

Of course, as Richard recalled, the first railway line around here was the Auckland-Newmarket link which started service in 1873, about 11 years after the idea was first mooted. Plus ca change, again.

But, he added, we were not travelling over that link but the more recent Westfield deviation, built to serve the old Westfield freezing works where, as it happens, my father started work as a 12-year-old boy, later rising to become general manager of the Auckland Education Board. Ah, memory lane.

From his vast horde of railway trivia Richard noted that the junction where the two lines meet is now point 666 - the number of the beast, as I recall - on the Wellington-Auckland line and point zero for the Auckland-Northland line.

By now we were passing through rather less attractive scenery, consisting largely of the rear yards of factories and fences decorated with grafitti, so Richard pulled out some of his railway memorabilia. This included pamphlets for some of the Overlander's predecessors including the Silver Fern, Silver Star - now revamped as the Eastern & Oriental Express and providing a luxury service between Singapore and Bangkok - Scenic Daylight and Blue Streak.

"I've got piles of this stuff and thousands of photos," he said.

"I always took my camera out on the job and I've always hung on to the old brochures. I guess you have to be a railway nut."

Suddenly we had left the city behind and the fields of Drury were on either side. The train sped up, too, and I could even hear the old familiar clicketty-click.

"Ah," said Richard, "you don't hear that often since they welded the rails. You only get it now in places where the welds are a bit rough.

"Pity, really, because if you count up the number of clicks in 29 seconds you get the speed in kilometres per hour." He paused briefly to count. "Right now we're doing about 50kph."

But it's not only the clicketty-clicks that have largely gone. So have countless dairy factories, freezing works and stockyards, plus the stations which served them, even the giant Otahuhu Railway Workshops which once employed thousands. Richard remembers them all and was able to point to their remnants.

In a few places the old station buildings still stand, in others a small red shed with a tatty place name is all that remains, and often the only sign of busy stations of yesteryear is the gap between the tracks where the platform once stood.

Mercer, for instance, Richard recalls as a major rail centre.

"It was a watering stop for the old steam engines, had a big freight operation picking up sand, was a major refreshment stop and served as the rail link with the shipping service on the Waikato River. There was even a separate railway settlement, called Kellyville, on the hill above. It's all gone."

At this stage we're thundering across the Waikato Swamp and Richard cheerily points out that if we could view the track below we would see it "moving up and down by as much as 2-3 inches because it's floating on a bed of tea tree".

Here, too, is the first railway bridge he was responsible for building, across the Whangamarino Stream, which these days sits right under the famous roadbridge to nowhere. Richard produces a photo from his collection of the bridge under construction and notes proudly that, "It's still there 50 years later ... though they are talking of replacing it."

In the Waikato the scenery is pleasantly bucolic, with lush green fields, bright yellow flowers, peacefully grazing cows and the wide waters of the great river flowing gently alongside.

But as we enter the King Country the passing parade becomes more ruggedly spectacular. There are statues of sheepshearers, giant weta and huge kiwi. On the outskirts of Te Kuiti there's a great view of Te Tokanga-nui-a-noho, the magnificently carved and painted meeting house, built by Te Kooti in 1878 and presented to his Ngati Maniapoto protectors.

At Waiteti there's the first of a series of mighty viaducts, this one 36m high and 127m long, built across the great gorges carved by the rivers which rage across this craggy country.

Others follow in quick succession - the huge Makatote, 79m high and 262m long; Maunganui-o-te-ao, 34m high and 91m long; Taonui, also 34m high and 122m long; amd, further down the track, Hapuawhenua, 43m high and the longest of all at 414m long. All offer marvellous views of tumbling rivers, tall stone cliffs and lush bush.

At Poro-o-Tarao - a name I've always enjoyed because it seems to have resulted from a band of warriors joking about having to follow the backside of their chief Tarao up the hill - the only way to get the railway through the impenetrable country was by digging a 1km long tunnel. Richard comments that the tunnel was actually finished several years before the rail arrived "but it proved very useful for local farmers driving cattle between Te Kuiti and Taumarunui".

At Taumarunui, made famous by Peter Cape's song about "Taumaruni, Taumarunui, Taumarunui on the main trunk line," the refreshment room I remember so vividly has gone ... and that reminds me of pies. Time for lunch. But, tragically, when I head for the buffet car the last of the pies has just been snapped up. Sob.

Still, by way of compensation, the scenery outside is getting even more magnificent, with the Whanganui River flowing beneath and the snowcapped peaks of Ruapehu and Ngaruahoe rising on the left.

And, just ahead, is the most impressive bit of engineering on the whole of the North Island Main Trunk Line - the extraordinary Raurimu Spiral - devised to overcome the fact that the climb up to the volcanic plateau was too steep for a railway to run.

Naturally, to a self-confessed railway nut like Richard, this is the holy grail, and his eyes light up as he explains that in the 5.5km gap between the settlement of Raurimu and the National Park Village the land rises 215m and along the route surveyed for the line in 1884 there would have been a gradient in excess of the one in 70 regarded as the maximum acceptable for rail.

This conundrum delayed the completion of the main trunk line for some years until in 1898 Robert West Holmes, a senior engineer in the old Public Works Department, came up with a brilliant plan which involved winding the line up the slope by way of a complete circle, three horseshoe curves and two tunnels, effectively spreading the climb over an 11.5km stretch and reducing the gradient to a mere one in 52.

"It basically means the trains circle their way round and round, up the hill," says Richard. "You actually pass the Raurimu station three times along the way. In fact there's an old story of a driver taking his train round the spiral who saw lights on the track ahead, pulled up to check what was there, and found he had caught up with the rear of his own train."

Sadly, Richard doesn't get to see the engineering masterpiece on this trip, because as a result of our train running late he and his wife have to swap over to the northbound Overlander, to return to Auckland, at Raurimu instead of the usual meeting point at National Park.

But he does give me a couple of brochures explaining the history of the spiral - known around the world as "a masterly example of railway engineering" - and I follow his advice to keep a look out as, sure enough, we pass the tiny Raurimu station on the right, then on the left, then on the right again. Remarkable.

We stop for a late lunch at National Park which has a fantastic cafe and, deprived of my pie, I devour a pork sandwich with a slab of meat a centimetre thick which is tender and delicious. The rest of the food looks great, too, and the station also has superb views of the volcanic peaks.

But, blow me down, when we get back on the train the new crew announce that they have found some extra pies which are being warmed up and will be ready to eat in about half an hour. Wouldn't you know it. We're getting off in about 10 minutes at Ohakune. So no Great Railway Pie for me this time.

There is, however, time for one more bit of history. A small cairn beside the track, near the Manganui a Te Ao River, marks the spot where on November 6 1908 the Prime Minister Sir Joseph Ward formally drove the last spike to complete the North Island Main Trunk Line.

That marked the end of a mammoth construction exercise which took 35 years, involved huge numbers of workers toiling in horrendous conditions, required some extraordinary feats of engineering ... and made possible my comfortable journey in the Overlander.

I've long been a fan of rail travel and I've done some amazing train journeys over the years.

The longest was from Beijing to Helsinki via the Gobi Desert, Mongolia, Siberia, Moscow and St Petersburg.

The most scenic - until now - was taking the famous Rocky Mountaineer and the lesser-known Skeena through the Canadian Rockies from Vancouver to Prince Rupert.

The most luxurious was the Eastern & Oriental Express from Singapore along the length of the Malay Peninsula to Bangkok.

The fastest was probably Japan's Shinkansen - or Bullet Train - from Tokyo to Kyoto.

The most nerve-racking, because of all the disruption caused by wildcat strikes by French railway workers, was from Venice to Paris, via Avignon.

And the most awful was in 1962 when I travelled from Whangarei to Dunedin by bus, train and ferry with the old New Zealand Railways.

But a few months ago, while having a chat with a man from KiwiRail, I realised that I haven't actually experienced our modern era of long-distance passenger rail, with daylight journeys in modernised carriages.

So one fine Friday morning my wife and I set off to see the country by rail - or at least as much of it as you can see by rail these days - filling in the gaps with public transport and having a few nice stop-offs along the way.

There was a bit of a stutter at the start when it turned out the bus in our part of Devonport didn't operate early enough for us to catch the ferry we needed. But a friendly neighbour dropped us at the wharf, the ferry did its usual cruise across the harbour, and we trundled our bags across Quay St to Britomart, from whence the Overlander was scheduled to depart at 7.25am.

We went from Auckland to Wellington on the Overlander; across Cook Strait on the interisland ferry Kaitaki; from Picton to Christchurch on the TranzCoastal; from Christchurch to Greymouth on the TranzAlpine; took a tour up the coast to Westport from where we flew back to Auckland on Air New Zealand; and, just to continue the public transport theme, caught the Airport Express into the city, took the ferry back to Devonport and trundled our bags down the seafront to home.

I wanted to avoid taxis if possible and we were easily able to walk from the stations to Holiday Inn Wellington and the Kingsgate Hotel in Greymouth. Christchurch Station is in the middle of nowhere but TranzScenic provides a free link with Canterbury Shuttles who whisked us off to the Hotel Grand Chancellor.

We also opted to stop along the way in Ohakune, Kaikoura and Cass.

But we could have chosen any of the 39 stations the three trains stop at, places like National Park, Waipara, Arthur's Pass or Lake Brunner.

At each of the three towns, we were able to stay at one of the fantastic lodges which have sprung up around the country in recent years - Ahuru Lodge at Ohakune, Hapuku Lodge at Kaikoura and Grasmere Lodge at Cass - and they all had courtesy cars at the station.

It was a great trip and a timely reminder that rail is arguably the best way to tour the country because you can enjoy the marvellous views without worrying about the driving, as well as eat and drink, read and type, go to the toilet and freshen up while still on the move.

Pity the passenger trains no longer go up north to Okaihau, or down south to Bluff, but we still managed to see much of the best New Zealand has to offer.